[CentOS] Installed Kernal (default)

Is there a description or statement that describes the stock kernal in 
CentOS, and would give all the various modules it is compiled with?  As 
with BSD, I assume there are things in the kernal that are mandatory, 
and then there are things that are optional or included so as to catch 
most everything one could have w/r/t hardware.  That being the case, as 
with FreeBSD, removing those unneded modules would work to reduce the 
size of the kernal.  Aside from rebuilding the kernal to have it contain 
certain objects needed for something to work, and the loading of 
different modules at runtime, are there any other benefits to building a 
custom kernal for any particular set of hardware?  By leaving the 
modules not needed, how much, if any, overhead does this contribute to 
size? 

Is this sort of the way things work under Linux, or am I all wet in my 
thinking?


-- 
Snowman